Portable wireless devices such as mobile phones have evolved into devices that transmit and receive data as well as voice information. The primary user interface for a portable wireless device is its keypad. Unfortunately a typical portable wireless device keypad can only accommodate about 12 keys.
The keypad is primarily responsible for providing an input means for numerical digits so that telephone numbers can be dialed. With expanding data and navigation capabilities, however, the typical keypad is being pressed into extra duty. Current keypad designs stamp multiple alpha-numeric characters on each key to indicate that any of these characters can be input. The primary input for each key remains its numerical value. To input one of the other characters, the user is required to press the keypad multiple times within a short time period. This has the effect of toggling through the list of characters for that particular key. The portable wireless device's display is generally used to provide visual feedback to the user as she presses a key. This allows the user to know when to stop pressing a key when the desired character has been reached.
In addition to the printed characters on each key, the portable wireless device can provide for the input of many additional characters per key using the display and a software algorithm. The additional characters include punctuation, small icons, and the like that are used in text messaging and other messaging applications.
Currently, the overall user experience for numerical and text entry is cumbersome and unsatisfactory. For a user to “type” the address and content of a text message requires significantly more keystrokes than characters used.
What is needed is a keypad that can accommodate more characters without having to resort to multiple key presses of the same key.